i've just played another round, this time paying extra attention to tower spawns and units.
here is how it went:
first off, my previous comment on tower-spawn logic seems to be wrong. after the first unit is send, there seem to spawn a couple of towers quite rapidly, to around eight towers.
then there was a short break in spawns, followed by a slightly slower spawning of a few more tower.
then i saw another short break. by that time i could already send tanks and doing so seems to have triggered another slow spawning of a group of towers.
after that the towers seemed to spawn in irregular small groups but with a tendency to get slower over time.
i can't figure out the exact spawn logic with just this, but it at least seems to be unrelated to unit sending.
is it related money/income or just timer based with extra modifiers?
and now for the unit and tower performance:
basic units are just garbage. just two light-blue towers and stop any basic unit from getting through and that is guaranteed to be the case before the first wave has even ended. well, basic units are only meant bridge the gap to fast units so that is fine for now. a minor health increase would be nice though.
fast units are blazing through the map but are so very squishy that they hardly ever get to the second half of the map before dying. only the first three fast groups i send got even close to the end. this makes them also garbage, since they never actually scored any lives at all. here i suggest to increase their health by 1.5-2 times.
a drastic change i know, but i don't think anything below that would make them actually reach the end. at least not once 12+ towers are on the field, and that happens fast.
as for the high HP units, they were just as unstoppable as always. exactly two died before the unending caravan made it to the end and the others were at 80+% health still. this only changed near the end when enough towers were on the field get a few kills in. by then the average health dropped to 10-25%.
since they are the current game-ender units that is good enough. but once you have more unit types, they need to be adjusted. and if the game lasts only a few minutes longer and more towers spawn, the game becomes pretty much unwinnable.
as for the towers, the light blue towers shoot fast enough that two are enough to deny all basic units. and there are bound to be at least two in the initial rapid spawn of eight towers.
as for the other towers, i didn't really notice any kind standing out much. they all seem to shoot at similar power and speed. well, the yellow towers seem to be the slowest and strongest but not by much.
once the fast units are reliably shoot sown, the individual performance doesn't really matter anymore. and once the tanks are send the game is pretty much over.
i know i repeat myself, but you really need to add more units!
and maybe make the towers more distinct, like a noticeable slow/stun effect to the dark blue towers, a splash effect to red towers, etc...
last but not least, i found a bad bug.
after ending a match, it is not possible to play another round without re-loading the game.
when i try start a second match, no towers spawn, no units spawn and the income doesn't tick up.
i think the timer that runs in the background doesn't get reset right.