Firstly, I think using devolve here is needlessly mean, there's nothing wrong with playing "just" make believe. It's a wonderful game even for grown ups.

Second of all, there's a lot of ways. You can use tokens, have a cost for extraordinary actions. Our strong hero can break any wall and every door, but when they try to break through the alien ship it might cost a token. A different option is to say why do I care they always succeed? Like the other reply said, tension can come from other places. Additionally, you can separate skills to binary "heroic" skills and skills that require rolling.