Nice one, but I have to agree with Boolsheet, it is a bit too small.
Also nice to know that I am not the only one working on a TD game with this Lövely engine. Anyway, without hijacking your thread for my TD game, here are some suggestions I came up with for your TD:
- Increase the size of the game (or at least provide an option) by 2x
- upgrades:
----- are too cheap
----- are too strong
----- need maximum cap
, or enemies don't receive enough health boost by each passing wave
Edit: tested upgrade levels a bit: a level 5 tower (that I could build with the starting money) lasted until wave 39 (lost 1 life), level 6 tower could kill everything until wave 200 or so. Yeah... definitely needs some tuning

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Keep up the nice work!