There are some fantastic TDs that allow you to build your own walls in an open field, they just need to be explicitly balanced around that. Besides Desktop TD,

There are some fantastic TDs that allow you to build your own walls in an open field, they just need to be explicitly balanced around that. Besides Desktop TD, the other main classic of that subgenre is Bubble Tanks TD: https://armorgames.com/play/4962/bubble-tanks-tower-defense https://armorgames.com/play/4962/bubble-tanks-tower-defense