The Konami classic Contra came to Android last year, but despite the healthy dose of nostalgia, Contra: Evolution wasn't an awesome experience. The introductory price was $0.99, but the gameplay was bogged down by in-app purchases. Now the game has gone free, and the IAPs have been tweaked a bit.
As we all know by this point, Google doesn't have a mechanism for a paid app to go free then return to paid. So, this change is forever. Contra: Evolution seems to still have the same basic unlock rules, but the assortment of IAPs is a bit simplified. There aren't as many items to purchase up-front, but you're still dealing with a pricey dual-currency system.
We reached out to Konami PR to see if this was going to erase any purchased content like Tiny Thief did. The response was a bit cryptic, saying that was very unlikely. If you feel you have lost access to content that was purchased, make sure to get in contact with the developers. With no barrier to entry, Contra: Evolution might be worth checking out. Don't get to excited, though – it's still got issues.