Just played this for an hour or 2 and absolutely love it, I haven't gotten to destroy a train yet, but I guess that's in the game ? (I seen a train, and the train might or might not have survived :D) I hope there is also some large battles where you aren't flying alone, but with bot friendly's ? (It looks like it but i'm not sure) A story based campaign would be nice, but I love the work you put in to this, arcade style is fine for me, so ill keep it at that.
The upgrades are okay, but I did not get the feeling it did much, plane upgrades also are a bit lacking in how they feel the plane changing (but perhaps that's on me); Might be fun to make the decal's payable so its also a ingame-money sink !
Also something you could add is a flight training of sorts (fly through the hoops, ...) not that an Ace pilot such as myself needs it tho ! ;-)
If there is something I would want to add perhaps some field battle happening below (now the targets remain rather static, except for boats) ? in WW1 trenches where used, but again, this game is really nice; good job team !
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It's already possible to have a squad of helpers, although if I die, I can't switch to the backup; its over & out :(
As to people saying its too easy : not if you play a bit further :D