If you copy/paste the second TOML snipped with features, there are two issues:

1. It’s presented as multi-line, but TOML doesn’t support multi-line inline tables. You could show it as:

[dependencies.bracket-lib]
git = "https://github.com/thebracket/bracket-lib"
default-features = false
features = ["amethyst_engine_vulkan"]

2. cargo run doesn’t like this:

error: failed to select a version for `bracket-lib`.
versions that meet the requirements `*` are: 0.8.2

the package `testrust` depends on `bracket-lib`, with features: `amethyst_engine_vulkan` but `bracket-lib` does not have these features.

failed to select a version for `bracket-lib` which could resolve this conflict