This should get you to level 8 and 600+ kills: at start spend all 120 on level 2 greed. Once you get $120 buy level 2 speed. Bank to $270 and buy first slot and level 3 Damage. Bank $800 and buy level 5 greed. Bank $550 and buy level 4 Fire rate. Bank $400 and buy level 4 speed. Bank $800 and buy level 5 damage. Bank $750 and buy next equipment slot and level 4 shot speed. From there max out everything you can. Keep in mind you do not have to buy previous level upgrades to get higher level.
For example, you do not have to buy level 1 and 2 to buy a level 3 upgrade.
Do not unlock save level. Instead of spending the talent points on save level, apply it towards start level. Putting TP's on start level resets the XP of the level system. So for example if you have upgraded start level to 20 and reset, it also reset the level system, meaning to get to level 21 you only need 50 level points. Unlocking the save level attribute eliminates that reset. I have been stuck at level 258 for god knows how long.
Good start. All of the best idle games have a reset/gain. I would look into a way to incorporate that. You should put a health regen target to click to increase the health regen between tank battles (on top of the auto regen).
TMANC1 - The space bar takes off 5% of the tick time. 5% of 5 seconds is greater than 5% of 0.67 seconds, which is why hitting the space bar seems to do nothing. To solve your problem, there would have to be an upgrade to increase the percentage the space bar subtracts.
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current level = start lvl+farmed lvl. save system will save farmed lvl.