Across the Heavens: Starting with 500 Combat Power in Spirit Cage

Ling Tian struck it lucky: he transmigrated from Blue Star to the Spirit Cage world and was bound to a World Sign-In System. (In each world, the protagonist can sign in once to claim a reward, then complete the five missions the System assigns there to earn another reward. With the System's help, he can then break through the world's barriers and travel to the next one.) (The planned worlds include mecha, high-martial-arts, Dragon Ball, Battle Through the Heavens, and cultivation worlds.) With the System's help, he solves the problems in the Spirit Cage world, then travels to other worlds and conquers them one by one. Finally, he returns to the real world and helps the Dragon Kingdom on Blue Star achieve a technological boom. (Note: a combat rating of 500 does not put him on par with Dragon Ball characters. If you thought this was an invincible-protagonist story, you've wandered into the wrong place!!!!! After all, I'm planning to write a Dragon Ball arc 😂)