This guide contains some tips to get Only Ballista achievement in the Rogue Tower game.
How to Obtain Only Ballista Achievement
- Win by building only ballista towers.
General advice would be, start with resetting your upgrades, and only take the cards that you’re going to use.
After you take all the Ballista, Mortar, and Tesla skills (because those start unlocked), and all the Status effect cards, you might need one or two more weapons to meet you Buy More Cards quotas. Just pick something like Encampment, which has a lot of cards, and buy them all, then never select the Encampment card in the game (if you do, your one dud card will turn into 4). I’d recommend not taking Life Steal or Haunted House.
Once you have all the cards and permanent upgrades you can use and nothing else — you can beat it with a status and crit build, on a good map. A good map for Ballistas, is a single path that turns 4-8 tiles into one loop-around rectangle. Then, you get all your range upgrades, and build in the middle of that space with a lot of ballistas upgraded a moderate amount.
I recommend you max out the poison and bleed trees, but for burn, only get the first level of the status application (+25% burn), and ignore the burn tree entirely. If possible, don’t even unlock it. You just don’t get enough cards to max out reasonably max out ballista and all three statuses in time. Applying just a little burn will stop armor from regenerating, though. Compensate for this by creating Armor-focused Ballistas set to MostArmor MostArmor MostArmor. I chose Burn, because the 5% Crit and 5% Slow from the other two trees are more useful.
Then you basically just play normal, focusing on Banditry, Ballista upgrades, Poison+Bleed upgrades, and universities if you see shrines (get the university cards, place down all the universities and upgrade them ~6-9 times per building and stop).
Have a front line, that does all the big damage. Watch the waves move through your line, identify what type of health is surviving the longest, and react by creating ballistas focused on that type of health set to MostWhateverx3 target priority. Have a couple back lines a good 5-10 tiles past that, which are meant to catch small enemies hasting out of the front line.