Blobware This first 2D game is just the very first step you could make learning Godot. Congratulations for this little achievement, still the road is very very long.
I ca n only suggest looking for Godot tutorials everywhere they are, especially on youtube, there are nice channels like GDQuest, Mister Taft Creates (there is a long series on Match3 game), Emi (for simple 2D game very different from Dodge the Creeps), GDQuest also provides some "simple" games like Harvester.
In order to actually learn, you'll have one day to dive yourself into actual game programming and designing. Take some knowledge here or there and mix them with your own recipes, you can use some of these tutorials as base, add one thing then another.
I advised you to work on what you can almost actually do, too high and you'll be overwhelmed and disappointed, like a platform game full of features. Find something you want to do and will keep you motivated all along the way full of hazards. Making game is surely not easy. You can add feature to Dodge the Creeps like bigger screen, more creeps, bonus, menus, and turn it into something crazy like Void Scrappers for instance.