Since the standard game does not come with winning conditions and is designed to go on indefinitely, here are several winning conditions you can use to test your skills.
These are the different board configurations for end game winning conditions, and win conditions in and of themselves.
A finished board
This is the first winning condition, and the minimum requirement for all other winning conditions. It is a fully explored, fully upgraded board. This means each tile is black and has all adjacent upgrades applied.
A complete board
A complete board features all different tiles and possible upgrades.
A finished board.
End Game Winning Conditions
These winning conditions concern clearing the board. The end game starts when:
- (1) All tiles are fully upgraded and;
- (2) each hex other than your own has an exploding bug spawning on it.
A (completely) clear board
A (complete) board you are guaranteed* to be able to clear every round.
You can use any number of moves each round in order to completely clear the board indefinitely.
A (completely) perfect board
A (complete) board you are guaranteed* to be able to clear every round with an identical sequence of moves. This sequence of moves starts and ends on the same hex and cannot be cut short by killing the final bug before the full sequence of moves has been completed.
This final winning condition only concerns itself with regular waves, waves with the upgrade bug are not taken into account except that you have to be able to guarantee a starting position for the next (regular) wave (ie kill the upgrade bug in a specific place).
* On guaranteed clearing conditions. I don't want to spoil too much, but there seems to be one inconsistency in the game that might end up being a factor late game. In case you don't want to find out for yourself: One thing you will likely discover at some point especially when attempting a perfect board, is that explosive stripping hexes upgraded with the hammer - which also clear bugs of armor and/or explosives on adjacent hexes - do not appear to work consistently on spawning. Sometimes it manages to clear them of both, sometimes of only armor, sometimes neither. It does appear to work consistently after spawning.
There is a way around this. If you don’t want discover it for yourself, you can see it in the linked example of the perfect board.
A perfect board (not complete). This 16 moves pattern could have been 2 moves shorter.
If you like the game but lack a goal, here are some ideas to go on. I would simply start by trying to build a finishing board and work your way from there.
There is quite some strategy and tactics involved with planning, building and revamping your board. Especially when building a board for the perfect end game challenges you'll likely find it'll make the mid game (at around waves 30-70) much harder than it otherwise would be, but that makes it fun.