System Requirements
The 4.5 update included upgraded graphics that changed the system requirements slightly. The minimum system requirements to run both games remained identical, but for the game to run at optimum settings one major system requirement changed. Optimum settings for version 4.0 require a video card with 256 megabytes of dedicated memory and the capacity to render pixel shader 2.0; the optimum settings for version 4.5 require a video card with 500 megabytes of dedicated memory and the capacity to render pixel shader 3.0. Other than requiring a more advanced video card, all other system requirements remained identical for both versions.
Visual Effects
The major addition to the version 4.5 visuals is a new bloom effect that manipulates the lighting to enhance the depth of view. The game's physics engine also received a slight upgrade that makes the behavior of the planes and helicopters appear and feel more realistic. With these these two enhancements, version 4.5 looks better and responds more realistically to the controls than version 4.0.
Gameplay
Version 4.5 also added to version 4.0's game play possibilities by including float planes and new water tracks. The addition of float planes gives you an opportunity to learn the dynamics of landing on water and experience what piloting a remote controlled float plane might be like in real life. Version 4.5 also included night flying, which didn't really change the core mechanics of the game like the addition of float planes, but added a new visual backdrop for flight to take place. Night flying also added new plane customization through the addition of light features to illuminate a plane.
Miscellaneous Additions
Some miscellaneous additions version 4.5 introduced to 4.0 are a more detailed and comprehensive plane editor and new flight track editor. The editor in version 4.5 builds upon its predecessor through the addition of new plane parts, more aesthetic customization options and a new model view mode that simplifies making changes. Version 4.5 expands the flight zone of previous tracks and includes the ability to edit the flight track of a flight zone by customizing aspects such as wind conditions and take-off space.