Sentinel Is Tower Defence In A Music Sequencer

I do like a good music-game hybrid thing. I also rather enjoy tower defence. Both of these things bode well for the appreciation of musical tower-defence game Sentinel, “which mixes strategic gameplay with a dynamic music system,” as solo developer Matthew Brown explained. He went on to expand on this by saying: “The game takes place on a sequencer-like grid. As you add defenses, collect resources and destroy enemies, musical elements are triggered in time to the backing music.”

Interesting, eh? More details below.

A release trailer:

A little more gameplay explanation in this Greenlight trailer:

Sentinel is out now on Humble Store.

For the sake of clarity, The Sentinel is this timeless Crammond masterwork, of course, and has been out since 1986.


  1. trjp says:

    I love the look – I like the idea but I think I need to try a demo, because there’s only so much TD a man can take…

  2. RaveTurned says:

    I am interested. Unfortunately I’m not getting much of a sense of how the gameplay shapes the music from either of those videos. :/

    Are there more informative videos out there? Even better, is there a demo available?

    • Glassmoon says:

      Hi Developer here,

      To clarify the music elements there are 16 steps along the grid much like a sequencer, and a beat line that moves across it. If a tower is present in the current ‘step’ it triggers a musical note at that point in the music. On top of that there are chord stabs when enemies are destroyed, riffs that trigger on certain events and additional layers that can mix in.

      I’m working on a demo at the moment and should have something ready in a few days.

      • GeeKay says:

        I’m very intrigued to, but agree that the video doesn’t give a sense of how it operates. I would greatly welcome a demo. Cheers :)

      • RaveTurned says:

        Thanks for the response, and your explanation. :) I didn’t notice any of the above when watching the video the first time – the beat line and the waves coming off the towers when they trigger are pretty subtle. I think once they’ve been scaled to fit into the embedded window they become a bit lost in the against the dynamic background visualisation. That said though, now that I’ve watched in full screen knowing what I should be looking for, I feel a bit idiotic for not seeing them the first time around!

        Glad to hear there’s a demo coming, I’ll look out for it. :)

  3. Thirith says:

    Am I the only one who thought of this first? And boy, do I feel old now…

    • neems says:

      Nope, you’re not the only one… I got very excited there for a moment. Although Sentinel Returns sucked, so I don’t really know why.

      Is it still possible to play the original Sentinel at all?

      • GeeKay says:

        link to

        An old but very good remake of it. The Sentinel was one of my favourite Speccy games.

        • Javier-de-Ass says:

          zenith is another, newer, good remake of sentinel. link to

          • says:

            That looks good. Shame about the lack of meanies, tho’. They did have a purpose: the Sentinel used them to jump you somewhere else if he or the sentries didn’t have line of sight.

      • Jams O'Donnell says:

        Sentinel Returns was actually rather good, I thought. Certainly more approachable than the original, which tiny me could never quite get his head around despite being fascinated by the landscapes (I just wanted to explore).

      • says:

        I’ve found my old DOS copy of the original game along with a list of codes for 4.23% of the game’s 10 000 levels (no, that’s not a typo :D ). I’ve uploaded it here: link to

        It still runs under XP, but for Vista and up, you’ll need a DOS emulator.

    • Jim Rossignol says:

      0/10 for not reading the article!

  4. Gap Gen says:

    I tried to stop the beat with a series of well-placed towers, but it turns out that in the end the Junior-Senior Axiom still holds.

  5. TheZkip says:

    Wow, the idea is strikingly similar to what we did as a student project half a year ago (link to Interesting to see how similar the mechanics will be. One thing I can say that ours is a lot more chaotic and fast-paced. Also, yours is of course much more polished looking. Love the style! (Actually I wanted to pursue something similar in our project, but the others members of the team sort of shot it down lol.)

    You’ve got one instant greenlight vote from here and I’ll have to buy&try the game right now –>

    • Kevlmess says:

      Another member of said student project here (howdy!) – it’s really, really similar! It feels kind of weird and cool that someone else, somewhere else, had almost exactly the same new idea for a game at roughly the same time.

    • Glassmoon says:

      Yeah looks like we both started from the same core idea, and just ended up in slightly different places. I really like the idea of extending the level horizontally so that the towers are looping over a number of bars based on the width of the level.

  6. Slaaneshi Cacophony says:

    Let’s not forget Judas Priest’s best track:

  7. Pnikosis says:

    “The way they are placed, my towers are poorly defending my base… but they sound awesome”.

  8. strangeloup says:

    I’m rather tempted to give this a flutter for a mere $10. The aesthetic reminds me pleasingly of Q? Entertainment‘s musicy games, which is about the best praise I can give a game of that sort.

  9. AvistTorch says:

    See, *this* is how you do “tower defense with a twist”.

    I still dislike the genre and am unlikely to take the plunge here, but I’m glad to see there’s some innovation left in the field.

  10. Snack says:

    Very similar at least in graphic style with Vector TD. link to

  11. Arglebargle says:

    Did my duty on Greenlight! Though I rarely use quantization…..

  12. DrGonzo says:

    I really hope its possible to add our own sounds to this game. A bit of an amateur music maker myself, so id love it if we can make our own sound packs or whatnot for it. Apologies if this is stated somewhere, on my mobile out in the arse end of nowhere at the moment.