Here is a quick run-down of what enve does:

• Timeline-based animation, automatic tweening, all objects’ and filters’ properties are animatable
• Supported objects: Bezier curve, ellipse, rectangle, text, brush strokes
• Uses MyPaint’s brushlib as the painting engine, relies on Qt’s native graphic tablets support
• Ships with a basic selection of blending and compositing modes for objects (Porter-Duff, as well as Screen, Overlay, Color Dodge, Color Burn etc.)
• Supports multiple scenes per project
• Imports image sequences, video and audio files
• Outputs anything that FFmpeg supports
• Has separation into core and GUI and supports pluggable path and raster effects, including GLSL fragment shaders
• Has configurable preview resolution for better performance control, you can use presets or input anything between 0% and 999%
• Works on Linux, can be made to run on Windows and macOS (Qt)

From the UX perspective, enve is a bit of a cross between Inkscape and Blender, which has a lot to do with Maurycy being an avid user of both, professionally. Just a few examples:

• You can use the path editing tool to edit rectangles and ellipses.
• When you edit a path, enve shows control points for two adjacent nodes so that you could easily tweak the shape.
• You can use G, S, and R shortcuts for moving, scaling, and rotating respectively, and for scaling, you can press X or Y to constrain the transformation to just one axis.
• The timeline design resembles that of Blender’s Dope Sheet, with the benefit of providing direct access to numeric values of various settings.
• Similarly to Bender, a panel can be duplicated vertically or horizontally, so that you could e.g. have access to different areas of the timeline or the canvas.